Lancashire Lightning (189/3; Croft 65*, Maxwell 58; Rimmington 2/30) beat Durham (117ao; S Steel 58; Parkinson 3/30) by 72 runs.
Durham suffered their first defeat of the 2019 Vitality Blast despite 58 from Scott Steel and two wickets from Nathan Rimmington.
The hosts set a total of 189/3 in their 20 overs, Steven Croft recording an unbeaten 65 opening the batting with Australian Glenn Maxwell also notching a half century.
Rimmington was the pick of the bowlers, removing Alex Davies with his first delivery – Dane Vilas his other victim.
Durham struggled to keep up with the run rate with only Scott Steel, Alex Lees and Brydon Carse reaching double figures.
Steel’s 58 came from 46 balls with four boundaries – all maximums.